The protein in fresh green plant tissues normally is separated from the fiber by mechanical crushing of the plant cell walls by hammer mills, rollers, screw presses or the like and squeezing the green juice from the plants.
Thereafter under prior practices the protein in the juice has been separated from the water in the juice by heating the juice to about eighty degrees C. or by adding mineral acids or organic solvents which coagulated the protein. The protein coagulum was then collected, usually by filtering or centrifuging. The usual procedure used prior to the present invention, including heating and the addition of solvents for obtaining protein from green plants is disclosed in a book by N. W. Pirie, Blackwell Scientific Publications, Oxford, 1971 entitled Leaf Protein, Its Agronomy, Preparation, Quality and Use.
The heating of the plant juice is expensive as is the addition of acid or organic solvents and in addition considerable equipment and energy is required to carry out the process by the heating method. The invention is directed to less expensive apparatus and process to coagulate and preserve the protein in the green juice expressed from green plants and to separate the protein from most of the water in the juice.